The present invention relates to an improvement of such plotters as use various kinds of pens and, more particularly, to a pen tip cleaning assembly for a drawing needle pen.
In a conventional plotter used in computer graphics or the like, various kinds of felt pens, ball-point pens, or drawing needle pens are prepared in a pen socket, and one of the pens is selected and held by a pen carriage so as to perform drafting. Especially, in such a plotter as is used for framing in newspapers, magazines or the like, a drawing needle pen must be able to draw very thin lines of 0.1 to 0.3 mm in width.
In a very thin drawing needle pen, when paper dust or foreign material becomes adhesive to a pen tip during drawing, or the pen tip tends to dry, ink is solidified at the pen tip. Due to this the pen becomes scratchy and the line thickness becomes irregular, and in a worst case, lines are not drawn at all. For these reasons, after drawing is performed for a predetermined period of time, the drawing operation must often be interrupted to remove paper dust and solidified ink from the pen tip by wiping it by cleaning paper. However, when simple manual cleaning is performed by an operator, the recording paper easily becomes soiled during the drawing operation. A cleaning operation requires skill and as a result, the pen tip cannot be sufficiently cleaned by manual operation. Furthermore, the operator may fail to clean the pen tip at a proper time, resulting in scratchy lines.